More on "Constraints." We need what I break down as "Co-Rotate" and "Screw-Nut" Constraints!
In the "Co-Rotate" category this would be a Constraint that creates a "rotational ratio" between two (if you will) "Constraints." In one case the "axis of rotation" are Parallel and the other the "axis of rotation" are Perpendicular. The two Entities either "Rotate in the Same Direction" (Clockwise or Anti-Clockwise) or they "Rotate in Opposite Directions" (Clockwise & Anti-Clockwise or Anti-Clockwise & Clockwise). My suggestion is that if the "Ratio" is "positive," then they "Rotate in the Same Direction" and, if the "Ratio" is "negative" then they "Rotate in Opposite Directions." This should be obvious if the "Axis are Parallel" and somewhat harder the define and visualize should the "Axis be Perpendicular."
In the case of "Axis Parallel Co-Rotate," this may be thought of as conventional gear trains, chain drives, belt drives, and the like. A chain or belt drive would have a "positive Ratio" whereas a gear train would have a "negative Ratio." More to the point, each type should have a (if you will) "Zero Alignment Position" from which the various "Ratios" begin.
In the case of the "Axis Perpendicular Co-Rotate," this may be thought of aa a "Worm Gear." This should be fairly self-evident. I expect a lot of "Right Hand Rule" noise to be involved in determining "Ratios," but not that great of a learning curve.
The case of a "Screw-Nut" Constraint should be the simplest to define. Each rotation of the "Screw" causes the "Nut" to move one "Pitch." If the "Pitch" has a positive value, then the "Constraint" creates a "Right-Hand Thread" relationship. If the "Pitch" has a negative value, then the "Constraint" creates a "Left-Hand Thread" relationship.
Just think of the power these "Constraints" would add to our abilities in Alibre Design !!!